This invention relates generally to a catheter device and methods for the site-specific delivery of agents to biological spaces in medical procedures. More particularly, the invention relates to a catheter device utilizing multiple balloons and a method of site-specific delivery of agents into the pericardial space for treatment of the heart.
Heart disease is the leading cause of death in the United States. One form of heart disease is caused by the formation of sclerotic plaques within blood vessels. These pathways prevent blood from flowing freely though vessels to the tissues the vessels supply. The most dangerous plaques are those which form in the coronary arteries, preventing the flow of oxygenated blood through the coronary arteries to the heart.
There are generally two surgical procedures for treating heart disease. One procedure involves methods to increase blood supply to the effected areas of the heart by clearing sclerotic plaques from the existing vessels. In angioplasty, for example, a small dilating balloon is inserted into the vessel to open the vessel to increase blood flow. A second procedure involves providing new pathways for blood flow. New pathways can be created by grafting in vessels (coronary artery bypass surgery) or by inducing the growth and development of new collateral vessels (therapeutic angiogenesis).
The induction of new collateral vessels can be achieved by injections of angiogenic agents directly into the heart tissue, into vessels (coronary arteries), or into the space surrounding the heart (pericardium). Direct injections of agents into the heart muscle or vessels can result in tissue injury, scarring and rapid washout of the agent into the peripheral circulatory system. Furthermore, these direct injections require surgical procedures which are more costly and require a longer recovery period than catheter based procedures. Thus, direct injections are not preferable. However, indirect injections into the pericardium avoid these difficulties.
The pericardium is a membrane that surrounds the heart and isolates it from the remainder of the body. The small space between the heart and the pericardium is the pericardial space, which is filled with pericardial fluid. The pericardial fluid is in constant contact with the heart muscle and coronary arteries and provides a relatively large reservoir for sustained release of drugs compared to intra-coronary methods or direct injection. Introduction of an agent to the pericardial space allows the agent to be contained in an area localized around the heart (epicardium and epicardial vessels). This is beneficial in the following ways: 1) a lower dose of drug can be used than if given systemically due to the low volume of the pericardial fluid, 2) the low rate of turn over of the pericardial fluid allows high concentration of the agent to be maintained over a longer period, and 3) it keeps the agents out of systemic circulation where the agent may cause adverse side effects.
However, the pericardial space is shallow, and thus difficult to access without puncturing (and damaging) the underlying heart tissue or coronary arteries. Previous attempts to access the pericardial space have utilized a syringe and needle combination, such as is used in pericardiocentesis, to directly inject agents into the pericardial space via the patient""s chest. One of the risks inherent in such devices is the tendency for the needle to go beyond the pericardial space and to pierce the heart muscle. Some devices have utilized suction to draw the pericardial tissue towards the needle and thereby limit the distance the needle has to travel to deliver fluid to the pericardial space.
One attempt to overcome some of the limitations inherent in procedures done through the patient""s chest is a catheter based system disclosed in U.S. Pat. No. 5,269,326 to Verrier, which has been incorporated by reference in its entirety. Verrier discloses the use of a catheter to approach the pericardial space via the right auricle, transvenously. The device takes advantage of the fact that the right auricle lies tangential to and between the pericardium and epicardium such that the catheter steered into the right auricle will be positioned substantially parallel with the wall of the pericardium. This approach minimizes the risk of damage to the pericardium or epicardium. However, using a catheter to pierce the pericardial wall can result in pericardial fluid flowing back into the atrium, blood flowing from the atrium into the pericardial space, and the therapeutic agent could end up being systemically administered.
Another approach to introducing medicaments directly into the pericardium is disclosed in U.S. Pat. No. 5,797,870 to March et al., which has been incorporated by reference in its entirety. March et al. discloses delivering a gene therapy agent into the pericardial sac either surgically or by transvascular means. In the catheter based embodiment the distal end of the catheter comprises a hypotube configured as a helical coil which is to be screwed into a heart wall to access the pericardial space. Like the device and method disclosed in Verrier, the device and method of March et al. is also susceptible to the backflow of pericardial fluid into the atrium and the ultimate systemic administration of the therapeutic agent.
What is needed, and what is provided by the present invention, is a catheter based device and method that accesses the pericardial space through the right auricle but is capable of sealing the access site so that the therapeutic agent is locally administered and flow between the auricle and the pericardial space is minimized.
The present invention provides an improved agent delivery catheter which obviates, for practical purposes, the above mentioned limitations.
One feature of the invention is a device for accessing the pericardial space while minimizing the risk of injury to the heart during the pericardial catheterization.
Another feature of the invention is a catheter device which minimizes leakage from the pericardium and bleeding from the atrium into the pericardial space during catheterization of a defined biological space, such as the pericardial space.
Another feature of the invention is to provide a catheter device which minimizes longitudinal movement of the catheter from a site-specific location during the delivery or collection of agents from a defined biological space, such as the pericardial space.
Another feature of the invention is a device having a lumen which communicates with the pericardial fluid for the site specific introduction of agents into or collection of fluid from the pericardial space.
In accordance with one aspect of the present invention, the catheter includes an inner shaft longitudinally movable within an outer shaft, wherein each shaft has at least one lumen within it and at least one balloon attached to it.
In accordance with an additional embodiment of the present invention, the catheter includes an inner shaft longitudinally movable within an outer shaft, wherein inner shaft has at least one lumen within it and at least one balloon attached to it.
In accordance with an additional embodiment of the present invention, the catheter includes an inner shaft longitudinally movable within an outer shaft, wherein each shaft has at least one lumen within it and at least two deployable wire supports attached thereto and includes at least one balloon attached therebetween.
The catheter may include at least one lumen in each shaft, wherein the lumen may contain a guidewire, a wire support deployment mechanism, a balloon inflation source, or an agent delivery or collection source.
The catheter may include marker bands on each shaft, such that the marker bands can be used to detect the position of the shafts relative to one another or relative to the pericardial space.
The inner shaft of the catheter may include a distal tip to penetrate the surface membrane of the biological space. The tip may further be radio-opaque so that its position can be detected during use.
The above described and many other features and attendant advantages of the present invention will become apparent from a consideration of the following detailed description when considered in conjunction with the accompanying drawings.